Answer:
Cytochrome C; it provides evidences that there is similarities in the respiratory pathways for producing ATPs by all living organisms especially mammals.
Explanation:
Cytochrome c is located in the intermembranes of mitochondria, and it functions in the transfer of of one electron in electron transport chain,(ETC) needed for generation of proton motive force; for generation of energy in the synthesis of ATPs by ATPase synthase during chemiosmosis. Its allows oxdation-reduction by the switching of its iron ii to iron iii. during electron transports.However its iron atoms does not undergo oxidation with oxygen. This feature makes it stable and an ideal carrier of electrons.
Its amino acid sequences is very similar in all living organisms especially between mammals(e.g man and chimpanzees)with little variation in few amino acid residues due to mutation.This similarity in its amino acids sequences in all living organism together with small molecular size makes it ideal molecular evidence for studying comparative molecular evidence of evolution.
This is because it can be used to trace the pathways of respiration to synthesize energy, and therefore to conclude that most organisms share common ancestry, since a very similar protein sequence in a structure(Cytochrome c) participated in unique ETC mechanisms in all, needed for energy synthesis .
A covalent bond is a chemical bond which involves the sharing of atoms.
